1822.] 
and laterally. Some other agent must, 
therefore, be looked for besides the 
mere expansive force. of the steam. 
This cause appears.to Mr. H. to be the 
explosion of hydrogen gas, arising from 
the decomposition of the water by the 
iron, and which under certain circum- 
stances comes. in contact with, the 
flame of the furnace. When the pres- 
sure) of steam is great, which it neces- 
savily aust be in the non-condensing 
engine, or When the feeding apparatus 
géts deranged, a sufficient supply of 
water is. prevented, and consequently 
some portion of the, bottom and sides of 
the boiler, which are in immediate con- 
tact with the fire, are left uncovered ; 
under these circumstances the parts of 
the boiler so. exposed are soon heated 
to redness, and the water that remains 
in its lower cavities in a state of ebulli- 
tion; coming at brief intervals over the 
red hot parts of the vessel, some portion 
of every wave is decomposed, and hy- 
drogen gas produced. If, in such cir- 
cumstances, the over heated metal is 
mielied: or burst through by pressure, 
thegas will rush through the aperture 
into the furnace, and, meeting with 
flame; will instantly be exploded. 
Another cause of the rapid destruction 
of steam-boilers arises from the impu- 
rity of the water employed, | At sea, or 
inrivers where the waters of the ocean 
have access, there is held in solution 
marine salt, and other saline and earthy 
matters, which are more or less depo- 
sifed.on the bottom of the boilers, in 
proportion(.to the quantity converted 
into steam. The waters of the greater 
number ‘of springs also, hold earthy 
wnatters in solution, which are likewise 
precipitated. in the same manner. 
This deposit, besides hastening the de- 
‘composition of the boiler, forms a hard 
crust slowly permeable by heat, which, 
re-acting upon the nietal, soon causes 
the destruction of some part.of the 
boiler.» If the foregoing views of this 
important subject are correct, and 
from the facts stated there seems to be 
no doubt but that they are so, it will 
follow that no precautions short of pre- 
venting the production and éxplosion 
of hydrogen gas, and the deposition of 
‘sediment on the bottom of the boiler, 
will prevent the recurrence ' of those 
terrible events, the subject of so much 
dread and alarm to the “public. | Mr. 
H’s boiler is ‘therefore formed ‘upon 
Acai which willeffectually obviate 
hese’great evils ; first, by insuring such 
New Patents and Mechanical Inventions. 
443 
a. supply of water as to keep the boiler 
always filled to a point above all the 
parts. that are exposed to the immediate. 
action. of the fire... This he accom- 
plishes by a water-regulating valve, so 
constructed as to descend with the wa- 
ter in the boiler, and by means of 
levers operating upon a valve in the 
steam-pipe to stop the motion of the 
engine altogether, before the water in 
the boiler can be so far exhausted as 
to leave any part of the inner surface 
of its bottom dry. And, secondly, by 
preventing the saline or earthly depo- 
sits from resting upon any part, or 
parts subject to the principal action of 
the furnace. ‘The tops of the flues in 
this boiler are the only parts in imme- 
diate contact with the fire; and, in 
order effectually to prevent any depo- 
sit from settling thereon, he places a 
shelf or shelves, saddle or saddles, of 
iron, wood, or other convenient mate- 
rials, horizontally, diagonally, or in 
any other position that may be judged 
best, in some part within the boiler, 
between the upper and lower surfaces 
of the water, to receive the earthy, sa- 
line, or other impurities, which may be 
precipitated from the water during its 
conversion into steam. From which 
shelf or shelves, saddle or saddles, the 
said deposits are either remoyed or al- 
lowed to precipitate into the cavities 
between the flues, and from thence 
taken away occasionally by means of 
proper doors or other contrivances for 
that purpose.— Repertory, 
To Mr. Cuarves TuELY, of Kenton- 
street; for certain Improvements on 
Window-Sashes of all Descriptions, 
which may be applied to Old or New 
Windows. 
These improvements on sashes are by 
making them turn, so that the outsides 
may fall inwards, which is done by 
fixing hanging stiles to the sides of the 
sashes, the hanging .stiles and_sash- 
stiles being so rebated as to render 
them weather-tight and connected by 
hinges, and so boxed in'each way to the 
stiles as to make ‘them: strong and 
durable. esai9 
Neither bolts nor fastenings are re- 
quired to prevent’ their turning when 
closed.’ The purpose of this invention 
is to avoid accidents: from getting on 
the outside of windows to clean, paint, 
or glaze them) also ta prevent their 
rattling by the wind, and for venti- 
lation, 
HYDRAULIC 
